A new route to prepare multiresponsive organogels from a block ionomer via charge-driven assembly

We report a novel route to prepare multiresponsive organogels through charge-driven assembly between a block ionomer and a diblock copolymer. The ionic complex aggregates to form spherical cores, which are connected by the middle block of the block ionomer to form gels. The organogels are responsive to acids, amines and salts.

Recent progress in the development and use of organic ionic plastic crystal electrolytes

Significant progress has been made recently in the development of Organic Ionic Plastic Crystals (OIPCs), a unique family of solid state electrolytes with applications in electrochemical devices such as lithium batteries and dye-sensitised solar cells. The negligible volatility of OIPCs renders them more suitable than molecular species for long-term device use, while the high thermal and electrochemical stability of many OIPCs fulfils an essential requirement for solid state electrolytes for many device applications. However, the complex mechanisms of conduction through these materials, both in their pure state and in the presence of a small amount of a second component (such as lithium salts to enable their use in lithium batteries) are still not fully understood. At the same time, the range of anions and cations utilised in the synthesis of plastic crystal phases continues to increase. This perspective concentrates on recent research into both fundamental and device-oriented aspects of these materials. Important fundamental understanding of the physical properties and transport mechanisms of different OIPCs has been achieved through use of techniques including variable temperature solid-state NMR and crystallographic analysis, as well as detailed molecular dynamics simulations. In parallel, the applicability of these materials as electrolytes for dye-sensitised solar cells and lithium batteries is being more widely demonstrated. The possibility of using OIPCs as solid state electrolytes for fuel cells is also discussed.

Ecological renovation of a constructed wetland

MasterFoods wetlands exhibit phytoplankton communities, yet no zooplankton to consume them. Macrophytes were planted to improve the water quality. However a lack of oxygen, methane production and highly soluble salts in the wetland water potentially disrupted osmoregulation mechanisms in both colonising zooplankton and submerged macrophytes, thereby inhibiting their survival.

A review of ionic liquid lubricants

Due to ever increasing demands on lubricants, such as increased service intervals, reduced volumes and reduced emissions, there is a need to develop new lubricants and improved wear additives. Ionic liquids (ILs) are room temperature molten salts that have recently been shown to offer many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and significantly reduce friction in the neat state. Recently, some researchers have shown that a small family of ILs can also be incorporated into non-polar base oils, replacing traditional anti-wear additives, with excellent performance of the neat IL being maintained. ILs consist of large asymmetrical ions that may readily adsorb onto a metal surface and produce a thin, protective film under boundary lubrication conditions. Under extreme pressure conditions, certain IL compounds can also react to form a protective tribofilm, in particular when fluorine, phosphorus or boron atoms are present in the constituent ions.

Protonated melonate Ca[HC6N7(NCN)3]·7H2O – synthesis, crystal structure, and thermal properties

Calcium hydrogenmelonate heptahydrate Ca[HC6N7(NCN)3]·7H2O was obtained by metathesis reaction in aqueous solution. The structure of the molecular salt was elucidated by single-crystal X-ray diffraction. The crystal structure consists of alternating layers of planar monopronated melonate ions, Ca2+ and crystal water molecules. The anions of adjacent layers are staggered so that no π–π stacking occurs. The melonate entities are interconnected by hydrogen bonds within and between the layers. Ca[HC6N7(NCN)3]·7H2O was investigated by solid-state NMR and FTIR spectroscopy, TG and DTA measurements.

Polymeric colorants: Statistical copolymers of indigo building blocks with defined structures

Statistical copolymers of indigo (1a) and N-acetylindigo (1b) building blocks with defined structures were studied. They belong to the class of polymeric colorants. The polymers consist of 5,5′-connected indigo units with keto structure and N-acetylindigo units with uncommon tautomeric indoxyl/indolone (=1H-indol-3-ol/3H-indol-3-one) structure (see 2a and 2b in Fig. 1). They formed amorphous salts of elongated monomer lengths as compared to monomeric indigo. The polymers were studied by various spectroscopic and physico-chemical methods in solid state and in solution. As shown by small-angle-neutron scattering (SANS) and transmission-electron microscopy (TEM), disk-like polymeric aggregates were present in concentrated solutions (DMSO and aq. NaOH soln.). Their thickness and radii were determined to be ca. 0.4 and ca. 80 nm, respectively. From the disk volumes and by a Guinier analysis, the molecular masses of the aggregates were calculated, which were in good agreement with each other. Defined structural changes of the polymer chains were observed during several-weeks storage in concentrated DMSO solutions. The original keto structure of the unsubstituted indigo building blocks reverted to the more flexible indoxyl/indolone structure. The new polymers were simultaneously stabilized by intermolecular H-bonds to give aggregates, preferentially dimers. Both aggregation and tautomerization were reversible upon dissolution. The polymers were synthesized by repeated oxidative coupling of 1,1′-diacetyl-3,3′-dihydroxybis-indoles 5 (from 1,1′-diacetyl-3,3′-bis(acetyloxy)bis-indoles 6) followed by gradual hydrolysis of the primarily formed poly(N,N′-diacetylindigos) 7 (Scheme). N,N′-Diacetylbis-anthranilic acids 9 were isolated as by-products.

Anisotropic MRI contrast reveals enhanced ionic transport in plastic crystals

Organic ionic plastic crystals (OIPCs) are attractive as solid-state electrolytes for electrochemical devices such as lithium-ion batteries and solar and fuel cells. OIPCs offer high ionic conductivity, nonflammability, and versatility of molecular design. Nevertheless, intrinsic ion transport behavior of OIPCs is not fully understood, and their measured properties depend heavily on thermal history. Solid-state magnetic resonance imaging experiments reveal a striking image contrast anisotropy sensitive to the orientation of grain boundaries in polycrystalline OIPCs. Probing triethyl(methyl)phosphonium bis(fluorosulfonyl)imide (P1222FSI) samples with different thermal history demonstrates vast variations in microcrystallite alignment. Upon slow cooling from the melt, microcrystallites exhibit a preferred orientation throughout the entire sample, leading to an order of magnitude increase in conductivity as probed using impedance spectroscopy. This investigation describes both a new conceptual window and a new characterization method for understanding polycrystalline domain structure and transport in plastic crystals and other solid-state conductors.

An organic ionic plastic crystal electrolyte for rate capability and stability of ambient temperature lithium batteries

Reliable, safe and high performance solid electrolytes are a critical step in the advancement of high energy density secondary batteries. In the present work we demonstrate a novel solid electrolyte based on the organic ionic plastic crystal (OIPC) triisobutyl(methyl)phosphonium bis(fluorosulfonyl)imide (P1444FSI). With the addition of 4 mol% LiFSI, the OIPC shows a high conductivity of 0.26 mS cm-1 at 22 °C. The ion transport mechanisms have been rationalized by compiling thermal phase behaviour and crystal structure information obtained by variable temperature synchrotron X-ray diffraction. With a large electrochemical window (ca. 6 V) and importantly, the formation of a stable and highly conductive solid electrolyte interphase (SEI), we were able to cycle lithium cells (LiLiFePO4) at 30 °C and 20 °C at rates of up to 1 C with good capacity retention. At the 0.1 C rate, about 160 mA h g-1 discharge capacity was achieved at 20 °C, which is the highest for OIPC based cells to date. It is anticipated that these small phosphonium cation and [FSI] anion based OIPCs will show increasing significance in the field of solid electrolytes.

Modelling ion-pair geometries and dynamics in a 1-ethyl-1-methylpyrrolidinium-based ion-conductive crystal

Full conformational and energy explorations are conducted on an organic ionic plastic crystal, 1-ethyl-1-methylpyrrolidium tetrafluoroborate [C2 mpyr][BF4 ]. The onsets of various stages of dynamic behaviour, which appear to account for low-temperature solid-solid phase transitions, are investigated by using quantum-chemical simulations. It is suggested that pseudorotation of the pyrrolidine ring occurs in the first instance; the partial rotation of the entire cation subsequently occurs and may be accompanied by reorientation of the ethyl chain as the temperature increases further. A cation-anion configuration, whereby BF4 (-) interacts with the C2 mpy cation from the side of the ring, is the most likely structure in the low-temperature phase IV region. These interpretations are supported by (13) C nuclear magnetic resonance chemical-shift analysis.

General approach for electrochemical functionalization of glassy carbon surface by in situ generation of diazonium ion under acidic and non-acidic condition with a cascade protocol

Immobilization of catechol derivatives on GC electrode surfaces can be performed by in situ generation and reduction of nitrocatechol. We present the oxidative nitration of catechol in the presence of nitrous acid followed by electrochemically reduction of the generated nitro aromatic group to the corresponding amine group and its conversion to diazonium cation at the electrode surface to yield a surface covalently modified with catechol. In this manner, some derivatives of catechol can be immobilized on the electrode surface. Whole of the process is carried out in Triethylammonium acetate ionic liquid as an inert and neutral medium (pH∼7.0). Surface coverage can be easily controlled by the applied potential, time and concentration of catechol. After modification, the electrochemical features of modified surface have been studied. Also modified GC electrode exhibited remarkable catalytic activity in the oxidation of NADH. The catalytic currents were proportional to the concentration of NADH over the range 0.01-0.80 mM. This condition can be used for modification of GC surfaces by various aromatic molecules for different application such as design of sensors and biosensors. © 2014 Elsevier Ltd. All rights reserved.

Using a selective cadmium-binding peplipid to create responsive liquid crystalline nanomaterials.

A specific metal ion-responsive lipid liquid crystalline (LLC) dispersion system was fabricated, which can work in buffer solutions. The LLC matrix was prepared from phytantriol which spontaneously forms the reversed bicontinuous cubic phase in water, and a novel peptide-lipid conjugate (peplipid) consists of a myristate alkyl chain for anchoring into the phytantriol-based cubic bilayer and a peptide sequence for capturing a specific metal ion. The peplipid in its unbound state, when added into the phytantriol-based cubic system induces a positive effect on the bilayer curvature, resulting in the formation of the lamellar phase (vesicles) and the dispersion was transparent in appearance. Upon binding of the cadmium ion, the peplipid induces a negative effect on the lipid bilayer curvature and consequently leading to the formation of cubic phase and opaque appearance. In contrast, other metal ions, including buffering salts, could not sufficiently trigger the phase transition due to weak interaction with the peplipid. The high selectivity of metal ion interaction and triggered phase transition provide potential applications, such as in colloidal-mineral separation, triggered drug release and treatment of cadmium (II) pollution.

Monoethanolamine reclamation using electrodialysis

Monoethanolamine (MEA) is the benchmark solvent for the capture of carbon dioxide from both natural gas and flue gas streams. Despite its effectiveness in absorbing CO2, this solvent can react with impurities in the gas stream to form heat stable salts and other degradation products. These impurities can cause problems such as an increase in solvent viscosity and corrosion of the operating units. Thus, a number of approaches have been considered to mitigate the occurrence of these problems. In this paper, the use of electrodialysis as an online MEA reclamation process in a postcombustion CO2 capture facility is investigated. The study shows that high heat stable salts removal can be achieved with a high MEA recovery. However, it is necessary to limit the current density, particularly at lower salt concentrations, to reduce water splitting. The stability of the commercial ion-exchange membranes in the highly alkaline solvent is also investigated. The results show that the membranes are stable upon exposure to 30 wt % MEA for at least 4.5 months.

Ionic liquids for energy, materials, and medicine.

As highlighted by the recent ChemComm web themed issue on ionic liquids, this field continues to develop beyond the concept of interesting new solvents for application in the greening of the chemical industry. Here some current research trends in the field will be discussed which show that ionic liquids research is still aimed squarely at solving major societal issues by taking advantage of new fundamental understanding of the nature of these salts in their low temperature liquid state. This article discusses current research trends in applications of ionic liquids to energy, materials, and medicines to provide some insight into the directions, motivations, challenges, and successes being achieved with ionic liquids today.

Mitigation strategies of hydrogen sulphide emission in sewer networks - A review

Hydrogen sulphide (H2S) gas emission in sewer networks is associated with several problems including the release of dangerous odour to the atmosphere and sewer pipe corrosion. The release of odour can endanger public health and corrode sewer pipe walls. Sewer corrosion has the potential to cost water utilities millions of dollars to maintain and rehabilitate the affected sewer pipes. Some chemical mitigation strategies to control hydrogen sulphide emission have been introduced. These include but are not limited to the injection of oxygen, magnesium and sodium hydroxide, calcium nitrate and iron salts. The optimisation of the dosing rate and location of each chemical mitigation strategy is required to achieve maximum hydrogen sulphide gas removal efficiency along with cost effectiveness. In this review paper, the five most popular chemical mitigation strategies that were previously mentioned have been investigated and discussed. The article is broken down into three main discussions. Firstly the sewer transformation processes and factors affecting the hydrogen sulphide generation and emission are highlighted. Secondly, comparisons and differences between each selected chemical mitigation strategy as well as its application covered. Finally, the review of the chemical efficiency and cost is conducted by comparing two case studies in controlling the formation of dissolved sulphide. It was found that the injection of oxygen is the cheapest mitigation strategy of hydrogen sulphide gas generation in sewers, but least effective.